1. Field of the Invention
The present invention relates to the cardiovascular medical field and more particularly to methods for evaluating cholesterol (lipoprotein) metabolism and screening patients who have a genetic predisposition for atherosclerosis.
2. Background of the Invention
Atherosclerosis is the underlying cause of the majority of cardiovascular disease related deaths in the Western Hemisphere. The clinical effects of atherosclerosis result from the formation of plaque and blood clots within the lining of blood vessels which lead to arterial stenosis. Atherosclerosis at its worst has debilitating effects on blood flow to critical organs of the body and is the major cause of heart attacks and strokes in patients. Attempts to alleviate or reduce the etiology of atherosclerosis have been met with only modest clinical success.
While several risk factors have been linked to the disease, studies have shown that an elevated serum cholesterol level is one of the main causes of atherosclerotic plaque formation. Cholesterol itself does not exist in a free-form in the circulation, but rather in macromolecular forms of low density lipoproteins (LDL) and high density lipoproteins (HDL). Modified (oxidized or acetylated) LDL is the harmful moiety of cholesterol. Plaque formation results when the homeostasis of lipid metabolism is unbalanced leading to an excess of modified LDL. Recently, it has been found that hypercholesterolemia (elevated blood cholesterol levels) is not solely related to dietary intake of cholesterol. Regulation of serum cholesterol levels is controlled by three variables: dietary intake, endogenous production, and cellular metabolism.
Of these three, cellular metabolism is the most important variable in regulating serum cholesterol levels. This inducible system is regulated in most individuals with elevated serum cholesterol levels. It is believed that the clinical management of certain patients having elevated cholesterol levels would be improved if their cellular metabolism for cholesterol could be evaluated in a comprehensive manner. Thus, a need exists for diagnostic methods for evaluating cholesterol metabolism in patients.